1. Pfizer and Icon and Parexel

When Pfizer announced two years ago that it needed to cut billions of dollars from its R&D budget, it looked for new avenues to trim costs. Aside from the typical round of layoffs, the pharma company turned to a CRO, or two in this case, to help it do just that.

Enter Parexel and Icon, two of the highest-grossing CROs around, which signed on to become Pfizer's preferred providers for clinical work in the 5-year deal. For the pharma company, the agreement allowed the CROs to handle the bulk of the work, while allowing Pfizer to maintain complete oversight in the clinical process, something that payers are still advocating for today.

"The two-partner model will simplify our processes, significantly reducing the number of external service providers we use for clinical trial execution, and clarify accountability in risk and quality management," said Pfizer's John Hubbard in a statement announcing the deal.

The financials of the deal have never been disclosed, though some experts speculate the deal is worth about $6.75 billion.